Field of the Invention
The present invention relates to a torque converter for a vehicle, and more specifically to a torque converter having a pair of bearings capable of withstanding thrust exerted on a stator.
Among torque converters used in a vehicle, there are many ones which have a lockup mechanism for improving fuel consumption by reducing a loss of power transmission energy in a high speed rotation of the vehicle engine.
The torque converters with the lockup mechanism include a housing, a pump, a turbine and a stator that are disposed within the housing, a drive plate or end cover connected with an engine drive shaft, and a lockup clutch disposed between the turbine and the drive plate. The lockup clutch is connected with a driven shaft via a turbine hub of the turbine and engageable with the drive plate for establishing rigid coupling of the driven shaft with the engine drive shaft in the high speed rotation. Thus, the power transmission efficiency can be increased.
One example of such kind of the torque converters has a thrust bearing mounted to the turbine hub so as to be rotatable relative to the stator. The thrust bearing includes a bearing race received by a recessed portion that is formed in the turbine hub. The bearing race is contacted with the recessed portion. The bearing race is made of an iron-based material. A retention disk opposed to the thrust bearing is mounted to a stator hub of the stator. The bearing race of the thrust bearing rotates in the recessed portion of the turbine hub during the operation of the torque converter. Since the turbine hub is made of an aluminum-based material, the recessed portion of the turbine hub suffers from abrasion caused by the frictional contact with the bearing race upon the rotation of the bearing race. This leads to shortening the life of the torque converter.
It is an object of the present invention to provide a torque converter having an extended life by preventing abrasion caused on a portion of the torque converter that receives a bearing race of a thrust bearing.